Rename .tools to .mystools for Arduino IDE 2 (#688)

* The Arduino IDE considers the .tools directory
 special and warns if it finds .tools the repo
 * Added detection of .tools directory rename
 * Corrected README errata

References #672

.mystools/cppcheck/config/avr.xml

@@ -0,0 +1,17 @@
+<?xml version="1"?>
+<platform>
+	<char_bit>8</char_bit>
+	<default-sign>signed</default-sign>
+	<sizeof>
+		<short>2</short>
+		<int>2</int>
+		<long>4</long>
+		<long-long>8</long-long>
+		<float>4</float>
+		<double>4</double>
+		<long-double>8</long-double>
+		<pointer>2</pointer>
+		<size_t>2</size_t>
+		<wchar_t>2</wchar_t>
+	</sizeof>
+</platform>